Metro area air quality · 2025
Denver-Aurora-Lakewood, CO
Median AQI 58 (Moderate). 28.8% of monitored days rated Good across this metro's EPA monitoring network.
- 58
- Median AQI
- 28.8%
- Good-air days
- 0
- Unhealthy days
- 3%
- Cleaner than US metros
Denver-Aurora-Lakewood, CO posted a 2025 median AQI of 58 (Moderate) with 28.8% Good days
According to the U.S. EPA Air Quality System, the Denver-Aurora-Lakewood, CO CBSA recorded a median AQI of 58 across 365 monitored days in 2025, with 28.8% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The Denver-Aurora-Lakewood, CO CBSA's 28.8% Good-day share places it cleaner than 3% of US metros in 2025.
- Closest median-AQI peer
- Brownsville-Harlingen, TX (29.9% Good, median AQI 57) is the closest nationwide median-AQI peer to Denver-Aurora-Lakewood, CO.
- 2020–2025 Good-day shift
- Denver-Aurora-Lakewood, CO's Good-day share moved +12.0 points from 2020 to 2025 (median AQI -4).
- Median AQI
- Median AQI: 58
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Denver-Aurora-Lakewood, CO lands in the lower Good-day tercile (28.8% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs moderate, among the more polluted US metros, with a median AQI of 58 and 28.8% of 365 monitored days in the Good band.
- 58
- median AQI · Moderate
- 28.8%
- days rated Good
- 3%
- cleaner than US metros
- 122
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Denver-Aurora-Lakewood, CO metro's Good-day share rose from 22.0% to 30.2% between the 2024 and 2025 EPA annual releases, a change of +8.2 percentage points.
- Denver-Aurora-Lakewood, CO metro's Unhealthy-category days fell from 8 to 0 between the 2024 and 2025 EPA annual releases, a change of -8 days.
- Denver-Aurora-Lakewood, CO metro's peak single-day AQI fell from 174 to 122 between the 2024 and 2025 EPA annual releases, a change of -52 points.
- Denver-Aurora-Lakewood, CO metro's median AQI fell from 64 to 58 between the 2024 and 2025 EPA annual releases, a change of -6 points.
Denver-Aurora-Lakewood, CO lands in the lower Good-day tercile (28.8% Good), a thinner clean-air share than most CBSA peers here. Signature read: 28.8% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 58 over 365 measured days in 2025 (Moderate / Poor). The monitored-day split lands at 105 Good (29%), 243 Moderate (67%), and 17 Unhealthy-for-Sensitive-Groups (5%). The 90th-percentile AQI finished at 90; the highest single-day reading hit 122 (USG).
Across 2020–2025, Good-day share shifted +12.0 points and median AQI moved -4 (improving). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Brownsville-Harlingen, TX (29.9% good, AQI 57); Dallas-Fort Worth-Arlington, TX (28.2% good, AQI 59); Hanford-Corcoran, CA (34.5% good, AQI 57).
Air Quality Summary
Median AQI
58
Moderate
Good Days
28.8%
105 of 365 days
Max AQI
122
USG
Health Grade
Poor
90th pct: 90
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
105
29%
Moderate
243
67%
USG
17
5%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Denver-Aurora-Lakewood, CO metro area's air quality is rated Poor based on 28.8% good air days. No unhealthy air days were recorded in 2025.
Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.
How does the Denver-Aurora-Lakewood, CO metro compare?
How Denver-Aurora-Lakewood, CO compares
5-Year Air Quality Trend
Air quality is improving in the Denver-Aurora-Lakewood, CO metro. Highest Good-day share: 2025 (30.2%, 105 of 348 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 61 | 270 | 4 | 62 | 161 |
| 2021 | 88 | 207 | 17 | 64 | 177 |
| 2022 | 90 | 239 | 2 | 60 | 190 |
| 2023 | 72 | 264 | 2 | 64 | 179 |
| 2024 | 73 | 251 | 8 | 64 | 174 |
| 2025 | 105 | 243 | 0 | 58 | 122 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Denver-Aurora-Lakewood, CO (58).
Brownsville-Harlingen, TX
Median AQI 57 · 29.9% Good-day share
Dallas-Fort Worth-Arlington, TX
Median AQI 59 · 28.2% Good-day share
Hanford-Corcoran, CA
Median AQI 57 · 34.5% Good-day share
Salt Lake City, UT
Median AQI 57 · 32.9% Good-day share
Chicago-Naperville-Elgin, IL-IN-WI
Median AQI 56 · 29.9% Good-day share
Cincinnati, OH-KY-IN
Median AQI 56 · 26.0% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Denver-Aurora-Lakewood, CO's 0 (independent of median AQI).
Aberdeen, SD
0 unhealthy-or-worse days · median AQI 27
Aberdeen, WA
0 unhealthy-or-worse days · median AQI 22
Adrian, MI
0 unhealthy-or-worse days · median AQI 41
Akron, OH
0 unhealthy-or-worse days · median AQI 45
Albany, GA
0 unhealthy-or-worse days · median AQI 46
Albany, OR
0 unhealthy-or-worse days · median AQI 27
Frequently Asked Questions
How many unhealthy air days does Denver-Aurora-Lakewood, CO have? ▼
What is the air quality in the Denver-Aurora-Lakewood, CO metro area? ▼
Is air quality in Denver-Aurora-Lakewood, CO getting better or worse? ▼
What does AQI 58 mean for health? ▼
How does Denver-Aurora-Lakewood, CO compare to other metro areas? ▼
What is the 90th percentile AQI for Denver-Aurora-Lakewood, CO? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Denver-Aurora-Lakewood, CO, 2025. See our methodology for how AQI, median, and coverage figures are computed.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, Denver-Aurora-Lakewood, CO · 2020–2025